Sammie,
Allow yourself this little bit of time to grieve that this cancer has come back. It's difficult to get back to feeling "safe" after dealing with cancer.......then to finally get there and have it return is devastating, I'm sure. I'm also sure that you are hiding your feelings from your husband better than you believe you are.
After you get past the shock of accepting that his cancer is back, there are some things you need to do for your husband, your daughter and yourself. First and foremost, get his pain under control. That in itself will change alot of issues for both of you. Then see about getting him some counceling and possibly an anti-depressent. I believe once his frame of mind is healthier, so will yours be. Then take some time to read about all the many survivors on this board that had "tennis ball or golf ball sized" tumors in their necks. They had the same treatment that your husband is having and they are ALIVE and doing quite nicely. Show or read the posts to your husband, let him know that his cancer is treatable.
Best of luck to both of you.
Minnie